FERN FAMILY 39 



with a narrow sinus, attached centrally to the receptacle above 

 the sporangia (see enlarged sorus in figure). Veins free. 

 {Dryopteris rigida arguta Underw.) 



The Rigid Wood-fern, together with our Sword-fern, grows 

 in semi-moist places throughout the State. They are espe- 

 cially abundant and attain their greatest size in the foggy 

 coast mountains. Along the trails at lower and middle alti- 

 tudes of the Sierra Nevada one frequently sees their fronds 

 gracefully spread out in the lee of a protecting rock. These 

 beautiful fronds remain green throughout the year. On this 

 account, and also because of their hardiness, these ferns are 

 much prized for ornamental planting. 



13. CYSTOPTERIS. 



1. C. fragilis Bern. Brittle-fern. Stalks clustered, fragile, 

 \y A in. to 1 ft. long. Fronds 2 to 12 

 in. long, broadly lanceolate, smooth, 

 2-pinnate; pinnae oblong-ovate or tri- 

 angular; segments ovate or ovate- 

 oblong, obtuse, decurrent along the 

 more or less winged rachis, toothed 

 or lobed. Sori small, roundish, on the 

 backs of the veins; indusium delicate, 

 hood-like, attached by a broad base 

 to the veinlet below the sporangia 

 (not under them) and usually turned 

 back by them as they ripen, or wither- 

 ing away. (Indusia are best studied 

 when the sori are young.) {Filix fra- 

 gilis Underw.) 



This dainty, fragile fern is common 

 among damp rocks by streams and in 

 other moist, shaded places. In shape 

 and cut of the frond it resembles our 

 Woodsias, but it is lighter green in 

 color, much more delicate in texture, and somewhat larger 

 in size. 



14. WOODSIA. 



Small, dark-green ferns, fruiting freely the length of the 

 frond. Sori round, on the backs of free veins; indusium deli- 

 cate, attached to the receptacle beneath the sporangia which 

 it partly or wholly encloses at first, often early dividing into 

 irregular lobes, thus forming a fringe. (Indusia are best 

 studied in young sori.) 





